Method and apparatus for necking and flanging can bodies

ABSTRACT

A cylindrical can body is positioned between axially aligned necking and flanging dies which are forced together so that the dies force the can body ends completely into and onto the dies to neck and flange the can body ends. The dies are then pulled apart, with the can body being first clamped to the flanging die to pull the necked end of the can body from the necking die. The can body is gripped and held between its ends to allow the flanging die to be then pulled off the flanged end of the can body.

United States Patent 1 1 Wolfe METHOD AND APPARATUS FOR NECKING ANDFLANGING CAN BODIES [75] inventor: Wayne F. Wolfe, Belmont. Calif.

[73} Assignee: United Can Company, Hayward,

Calif.

22 Filed: Feb. 22, 1973 211 Appl. No: 334,692

[52] US. Cl 113/1 G, 113/7, 113/120 AA,

72/94 [51] Int. Cl B21d 41/00 [58] Field of Search..... 113/1 R, 1 G, 7,8,120 AA; 72/94, 354, 344

[5 6] References Cited UNITED STATES PATENTS 3.013.654 9/1935 Hothersall113/1 G 1928.454 3/1960 Laxo 72/94 Mar. 19, 1974 3.375.798 4/1968Obidowski 113/8 3.406.648 10/1968 Armbrusterm. 113/7 R 3.610.009 10/1971Franek 113/120 AA Primary ExaminerRichard J. Herbst Attorney, Agent, orFirm-Carlisle M. Moore [5 7] ABSTRACT 6 Claims, 8 Drawing Figures 22 29\23 I5 3O\V 46 37 mi Ti 45 "a 36 1 SOURCE OF SOURCE OF HIGH PRESSURE LOWPRESSURE AIR 1 AIR PATENTEDHAR 19 1974 3. 797.429 SHEET 3 0F 3 J L A B cD EF 6 H K M N o P IN CAN BODY NECKING DIE OUT OF MOVEMENT CAN BODY AIRAIR TO AIR 5JR QE'' NECKING DIE PILOT UNPRESSURED) AIR .TO CAN AIR 0N I5I= I5 AIR ON BODY GRIPPER (UNGRIPPED) RIPPED) (UNGRlPPED) IN CAN BODYFLANGING DIE OUT OF MOVEMENT CAN BODY AIR TO AIR OFF AIR ON AIR OFF IFLANGING 1- DIE CLAMP (UNCLAMPED) (CLAMPED) (UNCLAMPED) A BCDEFGHIJMNOP-METHOD AND APPARATUS FOR NECKING AND FLANGING CAN BODIES BACKGROUND OFTHE INVENTION This invention relates to the manufacture of threepiecemetal cans, i.e., cans having a can body made from a rectangular sheetof metal rolled into a cylinder with the edges being joined by asoldered lap extending the length of the cylinder, and two can endswhich are thereafter secured to the can body by rolling operations.

In recent years it has been found desirable to form a cylindrical neckof reduced diameter on one end of the can bodyfln subsequent operationsa can end of reduced diameter is fitted to the necked end of the canbody and secured thereto by a rolling operation which forms an end rimof a diameter less than thediameter of the can body. The other end ofthe can body is flanged outwardly,-a normal sized can end being thenfitted thereto, the edgesof the can end and can body flange being rolledto form a rim whose internal diameter is just slightly greater than thereduced-diameter rim of the necked end. Such construction enables aslightly smaller can end to be used on one end of the can, resulting insubstantial material savings when great numbers of cans are produced.Further, such construe tion enables the filled cans to be stacked on topof each other with the reduced-diameter end rim of one can nested in thenormal-diameter end of the necked can. This nesting is advantageous instores wherein cans are stacked on open shelves and also inmanufacturing operations wherein two cans are to be joined together andmerchandised as a single unit.

In typical can body-forming machines, a can body gripper grips theexterior of a can between its ends and holds the can in axial alignmentwith a pair of endforming dies, the dies being forced onto the end ofthe can to produce the desired shape on the can end. After forming, thedies are pulled off the can ends so that the can body is free to bemoved to the next station of operations. ln machines wherein the sameoperation is per formed at both ends of the can, i.e., if the can bodyis double-flanged or double-necked, little difficulty is experienced instripping the dies from the can ends, since the pull exerted by oneretracting die on the can body is balanced by the opposite pull exertedon the can body by the oppositely retracting die. Even if there is somesmall unbalance in forces on the can body as the dies are pulledtherefrom, the can body gripper can hold the can body against axialmovement. However, a severe problem exists if it is desired tosimultaneously neck one end of a can body while flanging the other end.With a typical end-flanging die there is very little frictionalresistance between the flanging die and the flanged can end thereon, andaccordingly very little force is required to hold the can against axialmovement as the flanging die is stripped therefrom. On the other hand,when a can body end is forced into a necking die and a cylindrical neckis formed thereon there is a considerable amount of frictionalengagement between the necked end and necking die and a substantialforce will be required to strip the necked end from the die. Forces inthe order of 25 pounds pull are often encountered in stripping neckingdies from cans. When both ends are necked, the high extraction force ofone die is balanced by the extraction force of the other die.

If one end is necked and the other end is flanged, the extraction of theflanging die provides substantially no pull to the can to hold the canagainst movement with the necking die as the necking die is retracted.As a consequence, substantially the entire force on the can body to holdit against axial movement with the retracting necking die must beprovided by the can gripper. Since the can gripper forces radiallyinwardly on the unsupported middle of the can, application of sufficientforce to the gripper to hold the can as the necking die is strippedtherefrom will result in a buckling of the can body.

SUMMARY OF THE INVENTION can body is firmly gripped, without danger ofdeformation thereof, as the can body is stripped from the necking die.

This object is achieved by forming an outwardly projecting flange on oneend of the can body as the other end is being necked, and by thenclamping the flanged end of the can firmly to the flanging die adjacentthe flange. Since the can body end is fully hacked and sup ported by thepilot portion of the flanging die, the clamping force on the can end canbe very substantial without fear of damage or deformation to the canbody. With the can body so held, the dies are forced apart to strip thecan body from the Thus, for this stripping operation, the grip on thecan body is, in effect, shifted from the can body gripper to theflanging die. After the can body has been stripped from the necking die,either completely or sufficiently so that little force is required onthe can to hold it against final stripping, the can body is unclampedfrom the flanging die, the can is held by the can body gripper and theflanging die is stripped from the flanged end. With both dies strippedfrom the can, the can body is free to be discharged from the can bodygripper.

Other objects and advantages will become apparent in the course of thefollowing detailed description.

I BRIEF DESCRIPTION OF THE DRAWINGS FIG. 2 is a longitudinal sectionalview of the necking die of FIG. 1, illustrating the relation of theelements thereof prior to insertion of the necking die onto the end of acan body;

FIG. 3 is a view as in FIG. 2, showing the relation of the necking dieelements when the die is fully inserted into a can body end;

FIG. 4 is a transverse sectional view of the can body gripper of FIG. 1;

FIG. 5 is a longitudinal sectional view of the flanging die of FIG. I;

FIG. 6 is a view, partly in section, of the flanging die, taken on line5--5 of FIG. 5;

FIG. 7 is a chart illustrating the time sequence of operation of thenecking die, can body gripper and flanging die of FIG. 1;

FIG. 8 is a generally diagrammatic illustration of the machine, showingcan entry and discharge and the position of the head at various stagesof the necking and flanging operations.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,and in particular to FIG. 1 thereof, wherein one head of a multi-headturret-type machine is shown, the machine 10 comprises opposed bellhousing members 11 and 12 each mounted in stationary relation to asuitable platform by conventional means (not shown). A hollow driveshaft 13 extends axially through the stationary bell housings, the shaftbeing rotatably journaled at either end in bronze bushings 14, andhaving a drive gear 15 keyed to one end thereof so that the shaft may berotated in the bell housings by means of a conventional drive source(not shown).

Fixed to shaft 13, within bell housing 11, is a support member 16 havingspaced-apart yokes 17 and 18 thereon to support the necking die shaft 19for axial sliding movement therein, the axis of shaft 19 being parallelto the axis of drive shaft 13. Necking die shaft 19 is square, orotherwise non-circular, in cross section and yokes 17 and 18 arecorrespondingly shaped so that the necking die cannot rotate about itsaxis in the yokes. The end of necking die shaft 19 towards the center ofthe machine comprises a necking die holder 20 which carries the neckingdie 21 thereon. Secured to the other end of necking die shaft 19 is acam follower roller 22 which rolls in cam track 23 formed in the outersurface of cam ring 24 which is fixed to bell housing 11. The cam ring24 extends completely around shaft 13, so that as the main drive shaft13 rotates in the housing, roller 22 will be moved along the stationarycam track 23, with the side walls of the track acting upon roller 22 toimpart the desired reciprocal axial movement to the necking die shaft19.

A corresponding flanging die shaft 26 is disposed inside b'ell housing12 and is mounted in yokes 27 and 28 for axial movement as cam followerroller 29 is moved along stationary cam track 30. The end of flangingdie shaft 26 towards the center of the machine comprises a die holder 31which has flanging die 32 secured thereto, flanging die 32 and neckingdie 21 being coaxial. Flanging die holder 31 also has can body clamps 33mounted thereon.

Secured to main drive shaft 13, centrally thereof, is a can body gripper34, adapted to grip and hold a can body 35 between and in coaxialrelation to the necking and flanging dies.

Air under pressure for operation of the necking die, flanging die clampsand can body gripper is supplied to the machine as follows. Low pressureair from air source 36 passes through a rotating union 37 at the driveend of the machine and into conduit 38 within drive shaft 13. Conduit 38extends through an opening in the drive shaft up to valve 39. Conduit 40then continues from valve 39 back within drive shaft 13, conduit 40being brought out and attached to passage 41 in base 42 of the can bodygripper 34 which leads to the piston cylinder 43 in base 42. Valve 39 isa conventional two-way valve having a depressible valve operator 44actuated by screw 45 mounted for axial movement on necking die shaft 19.When valve operator 44 is depressed, FIG. 1, valve 39 connects conduits38 and so that low-pressure air is delivered to the can body gripper 34.When the necking die shaft 19 has moved slightly to the left and screwhas moved therewith to relesase valve operator 44, valve 39 will closeconduit 38 to flow therethrough and will open conduit 40 to atmospheresso that air pressure in the can body gripper will then be vented.

High-pressure air from source 45 is delivered through rotating union 46at the free end of the machine and into conduit 47 within drive shaft13, through tee connection 48, and conduit 49 to valve 50. A flexibleconduit 51 extends from valve 50 to necking die shaft 19, conduit 51being then connected to the internal passage 52 which extends to thenecking die 21. Valve 50 on plate 53, which is fixed to drive shaft 13,has a cam follower roller 54 thereon for actuation of valve 50, roller54 being in rolling engagement with cam surface 55 on the cam ring 56fixed to bell housing 11. Valve 50 and the actuator therefore areconventional; when roller 54 is allowed by cam surface 55 to moveoutwardly, valve 50 connects conduits 49 and 51 so that highpressure airis delivered to the necking die. When cam surface 55 forces roller 54inwardly, valve 50 is actuated to close off conduit 49 and to ventconduit 51 to atmosphere.

Similarly, high-pressure air is delivered from the tee connection 48through conduit 59 to valve 60 and then by flexible conduit 61 to theinternal passage 62 in th flanging die shaft 26. In like manner, theinterengagement of cam follower roller 63 and cam surface 64 willoperate valve 60 to either connect conduits 59 and 61, or to shut offconduit 59 and ven conduit 61 to atmosphere. 7

Although the necking die may be of any construction which will form areduced-diameter neck on a can body end, preferably the necking die 21is of the type more fully shown and described in my copendingapplication, Ser. No. 320,895, filed Jan. 4, 1973 and entitled PilotConstruction for Necking Die Assembly, the description of whichisincorporated herein by reference.

In brief, necking die 21 comprises an outer die member having aninwardly facing cylindrical die surface 71 approximately the samediameter as the outside diameter of can 35, an inwardly tapered diesurface 72 which forms the shoulder on the can body and areduced-diameter cylindrical die surface 73 which forms the cylindricalreduced-diameter neck on the can body. As a can body end is forced intothe die, the can body end will engage and slide along the inwardlytapered surface 72 and be deformed inwardly thereby, the can end thencoming into engagment with the shoulder 74 on the internal polit 75.Continued insertion of the can body into the die causes pilot 75 to bepushed axially within the die assembly, against the force of spring 76,with the cylindrical, reduced-diameter neck on the can being formedbetween die surface 73 and the outer surface 77 of the pilot segments 78carried by the pilot (FIG. 3). As the can body and necking die are thenpulled apart, the pilot 75 is forced back to its original position (FIG.2) by spring 76 to assist in the initial stripping of the cam from thedie.

Necking die 21 is securely mounted on necking die holder 20 by screw 79,pin 80 being used to prevent rotation of die 21 on the die holder. Airunder pressure from necking die shaft passage 52 passes through theaxial passage through mounting screw 79 and to the interior of theflexible sleeve 81. When this sleeve is pressurized, it forces all ofthe pilot segments 78 outwardly to provide a firm support for the canbody end as it is being necked while allowing one or more of the diesegments to yield inwardly as the can lap 82 is inserted into the dieassembly.

Referring now to FIGS. 1 and 4, the can body gripper 34 includes aradially extending web 85 secured to the can body gripper base 42, onwhich are mounted two gripper arms 86 and 87, gripper arm 86 beingrigidly mounted on web 85 while gripper arm 87 is pivotally mountedthereon for rotation about the axis of pivot pin 88. Piston 89, slidablein bore 90 in base 42, is out wardly biased by spring 91 and engagespivotal gripper arm 87 to force it in a counterclockwise direction (FIG.4) so that the arcuate surfaces 86a and 87a of the gripper arms willgrip a can body 35 therebetween. Piston 92, in cylinder 43, isengageable with the pivotal gripper arm 87 on the other side of pivotpin 88. When air under pressure is introduced through conduit 40 andbase passage 41 into cylinder 43, piston 92 will be forced outwardly,causing the gripper arm 87 to pivot in a clockwise direction against thebias of spring 91 and thus release the grip on the can. In addition, asthe gripper arm 87 moves in a clockwise direction, the edge 87b of thearcuate gripper surface 87a will move outwardly, away from the axis ofdrive shaft 13, to eject the can body 35 from the gripper arms.

Referring now to FIGS. 5and6, the flanging die 32 comprises an outer,inwardly tapered guide surface 101, a cylindrical, outwardly facingpilot surface 102 of a diameter substantially equal to but very slightlyless than the inner diameter of the can body 35, and an out wardlycurved flanging surface 103. The flanging die 32 is received within dieshoe 104, the latter having a shoulder 105 at the end of the flangingsurface 103 to limit the relative movement ofa can body end onto theflanging die. Die shoe 104 in turn rests against core 106, and theentire flanging die assembly is secured to flanging die holder 31 bymeans of screw 107. Core 106 is longitudinally slotted, at 108 and 109,to receive clamp arms 110 therein, each clamp arm being pivotallymounted between its ends on core 106 by pivot pin 111, and provided witha clamp shoe 112 onone end thereof. Each clamp shoe has an arcuateclamping surface 113 of a curvature complementary to the outer surfaceof the can body being flanged, the clamp shoe being adapted to engagethe can body adjacent the flange formed thereon and to clamp the canbody firmly to the cylindircal pilot surface 102 of the flang ing die.Each clamp arm is biased outwardly by spring 114 the clamp arms havingsufficient pivotal movement about pins 111 so that the clamp surfaces113 can move outwardly beyond the die shoe shoulder 105. Core 106 isradially bored at 116 and 117 to receive pistons 118 therein, eachpiston being engageable with a clamp arm on the side of pivot pin 111opposite to spring 114. Screw 107 is providedwith an axial passage 119and lateral ports 120 so that air under pressure can pass'from theinternal passage 61 of flanging die shaft 26 through screw 107 and beexerted against the inner surfaces of pistons 118. When air underpressure is exerted against the pistons, they will move the clamp armsagainst the bias of springs 114 so that the clamping surfaces 113 moveinto clamping engagement with a can body on the flanging die. Release ofair pressure will then allow springs 114 to pivot the clamp shoes 112away from the flanging die. Preferably, the clamping surfaces 113 aremade of a plastic material, such as Delrin, so that the can body willnot be scratched or marred by the clamping surfaces.

OPERATION The operation of the machine is best described with referenceto FIGS. 7 and 8. a rotating can entrance make-up conveyor 125, having aplurality of magnetic can-holding pockets 126 equal in number to thenumber of heads on machine 10 and rotating in synchronism therewith,brings a can 35 into registration with can body gripper 34 when thelatter is at position A, approximately- 15 before vertical. At thistime, and as shown in FIG. 7, the necking and flanging dies have beenmoved by cam follower rollers 22 and 20 to their fully retractedpositions, as shown in FIG. 1. With the necking die retracted, valve 40has been actuated to supply air under pressure to the can body gripper34 so that the pivotal arm has been moved to open, or ungripped,position. Cam surface 55 has caused cam follower roller 56 to actuatevalve 50 :so that high-pressure air is present in the necking die pilot75, forcing the pilot segments 78 outwardly. Cam surface 64 has causedcam follower roller 63 to actuate valve to vent the flanging die coreallowing the springs 114 to maintain the clamp shoes 112 outwardly fromthe flanging die. As the main shaft 13 and the make-up conveyor 125continue to rotate,- stationary stripper arm 127 strips the cam bodyfrom pocket 126, the can body being held in the can body gripper by thespringpressed can retainer 128.

When the can body has reached position B, cam

tracks 23 and 30 begin to move the necking and flanging diessimultaneously towards each other. At position C, the necking die shafthas moved sufficiently far to allow valve 40 to vent the can bodygripper cylinder 43, in turn allowing spring 91 to move gripper arm 87into gripping engagement with the can body so that the can body is heldin axial alignment with the necking and flanging dies.

At position D the necking flanging dies have been brought sufficientlyclose together so that one end of the can body starts into the neckingdie and the flanging die starts into the other end of the can body. Atposition B, one end of the can body isat the beginning of the inwardlytapered die surface 72 of the necking die while the other end of the canbody is at the beginning of the outwardly tapered die surface 103 of theflanging die.

During the travel from positions E to F, the can body ends aresimultaneously outwardly flanged and inwardly shouldered, with the forceon the can body exerted by the flanging die being balanced by the forceimposed on the can by the shouldering portion of the necking operation.At position F, the flanged end has come into engagement with shoulder ofthe flanging die shoe 104 and the inwardly shouldered has come intoengagement with shoulder 74 of the necking die pilot 75. At this point,the flanging die cam track 30 stops forward movement of the flanging dieand holds the flanging die against axial movement. Also, at position F,cam surface 64 causes valve 60 to be actuated to supply air underpressure to pistons 118, causing the flanging die clamps to clamp firmlyagainst the flanged can body.

During travel from position F to G, the necking die continues to moveinwardly to form the cylindrical reduced-diameter neck on the can body.During this time axial thrust on the can body imposed by the necking dieis fully opposed by the stationary flanging die, and no thrust isimposed on the can body gripper 34.

From G to H, the necking die dwells and at H begins to be retracted byits cam track 23, and to be pulled from the necked end of the can.Although the necking die pilot is biased by spring 76, and the airpressure in the pilot, to its original position which will aid instripping the necked end of the can body from the necking die,considerable pull will be exerted on the can by the retracting neckingdie. This pull, however is fully opposed by the stationary flanging diewhich has the opposite end of the can body firmly-clamped thereoto. As aconsequence, there is no resultant axial force between the can body andthe can body gripper 34 during this stripping operation from the neckingdie.

At position I, the necking die pilot is in its original outward positionrelative to the necking die assembly, and cam surface 55 causes valve 50to be actuated to vent the necking die pilot, allowing the pilotsegments to collapse inwardly. The necking die continues to retract,with the flanged end still being clamped to the flanging die untilposition J is reached wherein no part of the necked can is in engagementwith the outer necking die 70. At this point, th air pressure on theflanging die pistons l 18 is vented, allowing springs 114 to move theclamps to their outer position. Also, retraction of the flanging die isstarted.

Such pull as is exerted on the can body by the final stripping of thenecked end from the collapsed necking die pilot is opposed by the pullexerted on the can body by stripping the flanging die therefrom.However, neither pull is of any great magnitude and little force isrequred to be exerted on the can body by the can body gripper even ifthese pulling forces are unbalanced.

At positions K and L, respectively, the necking and flanging dies havebeen stripped from can body, the dies continuing to retract until theyreach their original positions at position N.

Shortly before that and at position M, the necking die shaft causesscrew 45 carried thereby to engage valve actuator 44, to supply airunder pressure to the can body gripper. The force of the air on piston92 kicks pivotal arm 87 to open position, ejecting the necked andflanged can body downwardly and outwardly to can chute 129.

At some subsequent position P, valve 50 is again actuated to pressurethe interior of the necking die pilot. The elements are then carriedback to piston A to pick up the next can body for the next cycle ofoperation.

Having thus described by invention, I claim: 1. Apparatus forsimultaneously necking and flanging a can body comprising:

a necking die holder and flanging die holder mounted for movementtowards and away from each other,

necking die means for forming a reduced-diameter neck on the end ofa canbody when a can body end is forced thereinto, said necking die meansbeing carried by said necking die holder for movement therewith,

a flanging die carried by said flanging die holder, said flanging diehaving a cylindrical pilot portion adapted to be inserted into the endof a can body and an outwardly curved die surface at the end of saidpilot portion for flaring the end of a can body to form an outwardlyprojecting end flange thereon, said necking die means and said flangingdie being coaxial and spaced from each other,

means for gripping the exterior of a can body between the ends thereofand for holding said can body coaxial with said necking die means andsaid flanging die means,

means for forcing said necking die holder and flanging die holderstowards and way from each other,

can body clamp means having clamp surface thereon,

means mounting said can body clamp on said flanging die holder formovement therewith, and for movement thereon whereby said clamp surfaceof said clamp moves towards and away from engagement with saidcylindrical pilot portion of said flanging die adjacent the outwardlycurved die surface thereof, means for forcing said clamp surface towardssaid cylindrical portion of said flanging die and for moving said clampsurface away therefrom.

2. Apparatus as set forth in claim 1 wherein said can body clamp meanshas two clamp surfaces diametrically opposite to each other relative tothe axis of said flanging die, each clamp surface having an arcuatesurface thereon, the curvature of said surfaces being complementary tothe cylindrical pilot portion of said flanging die.

3. Apparatus as set forth in claim 2 wherein said clamp surfaces aremade of plastic material.

4. Apparatus as set forth in claim 1, wherein said means for moving saidclamp surface of said can body clamp away from the pilot portion of saidflanging die comprises a spring and wherein said means for forcing saidclamp surface of said can body clamp towards said pilot surface includesa piston engageable with said can body clamp and a controllable sourceof fluid under pressure for forcing said piston in a direction to movesaid can body clamp against the bias of said spring.

5. A method of necking one end of a can body with a necking die whichforms a shoulder and reduceddiameter cylindrical neck on the end of acan body and flanging the other end of the can body with a flanging diewhich forms an outwardly extending flange on the end of a can body, themethod comprising:

inserting the flanging die partially in one end of a can body andinserting the other end of the can body partially into the necking die,

forcing the dies relatively towards each other to insert the flangingdie completely into the can body and to insert the can body completelyinto the necking die,

clamping the can body to the flanging die adjacent the flange formed onthe can body,

forcing the dies relatively apart while maintaining the can body clampedto the flanging die during at least the intial stripping of the neckedend of the can body from the necking die and then unclamping the canbody from the flanging die,

multaneously on the can body ends, holding said flanging die againstaxial movement after the can body has been flanged and moving saidnecking die axially towards said flanging die to form the neck on saidcan body, holding said flanging die against axial movement until theflanged can body end is unclamped therefrom and holding the can bodyagainst axial movement as the flanging die is moved axially thcrellrom.

1. Apparatus for simultaneously necking and flanging a can bodycomprising: a necking die holder and flanging die holder mounted formovement towards and away from each other, necking die means for forminga reduced-diameter neck on the end of a can body when a can body end isforced thereinto, said necking die means being carried by said neckingdie holder for movement therewith, a flanging die carried by saidflanging die holder, said flanging die having a cylindrical pilotportion adapted to be inserted into the end of a can body and anoutwardly curved die surface at the end of said pilot portion forflaring the end of a can body to form an outwardly projecting end flangethereon, said necking die means and said flanging die being coaxial andspaced from each other, means for gripping the exterior of a can bodybetween the ends thereof and for holding said can body coaxial with saidnecking die means and said flanging die means, means for forcing saidnecking die holder and flanging die holders towards and way from eachother, can body clamp means having clamp surface thereon, means mountingsaid can body clamp on said flanging die holder for movement therewith,and for movement thereon whereby said clamp surface of said clamp movestowards and away from engagement with said cylindrical pilot portion ofsaid flanging die adjacent the outwardly curved die surface thereof,means for forcing said clamp surface towards said cylindrical portion ofsaid flanging die and for moving said clamp surface away therefrom. 2.Apparatus as set forth in claim 1 wherein said can body clamp means hastwo clamp surfaces diametrically opposite to each other relative to theaxis of said flanging die, each clamp surface having an arcuate surfacethereon, the curvature of said surfaces being complementary to thecylindrical pilot portion of said flanging die.
 3. Apparatus as setforth in claim 2 wherein said clamp surfaces are made of plasticmaterial.
 4. Apparatus as set forth in claim 1, wherein said means formoving said clamp surface of said can body clamp away from the pilotportion of said flanging die comprises a spring and wherein said meansfor forcing said clamp surface of said can body clamp towards said pilotsurface includes a piston engageable with said can body clamp and acontrollable source of fluid under pressure for forcing said piston in adirection to move said can body clamp against the bias of said spring.5. A method of necking one end of a can body with a necking die whichforms a shoulder and reduced-diameter cylindrical neck on the end of acan body and flanging the other end of the can body with a flanging diewhich forms an outwardly extending flange on the end of a can body, themethod comprising: inserting the flanging die partially in one end of acan body and inserting the other end of the can body partially into thenecking die, forcing the dies relatively towards each other to insertthe flanging die completely into the can body and to insert the can bodycompletely into the necking die, clamping the can body to the flangingdie adjacent the flange formed on the can body, forcing the diesrelatively apart while maintaining the can body clamped to the flangingdie during at least the intial stripping of the necked end of the canbody from the necking die and then unclamping the can body from theflanging die, gripping the exterior of the can body between its endswhile relatively moving the gripped can and flanging die axially apart.6. A method as set forth in claim 5 and further including holding saidcan body against axial movement during initial insertion of the flangingdie in one end of the can body And initial insertion of the other end ofthe can body into the necking die, moving both of said dies towards eachother to form the flange and shoulder simultaneously on the can bodyends, holding said flanging die against axial movement after the canbody has been flanged and moving said necking die axially towards saidflanging die to form the neck on said can body, holding said flangingdie against axial movement until the flanged can body end is unclampedtherefrom and holding the can body against axial movement as theflanging die is moved axially therefrom.